Using a clever combination of virtual reality and brain imaging, researchers have located a “homing signal” in the human brain, revealing why some of us are always getting lost while others navigate with ease. It all depends on signal strength and reliability (like wi-fi). The work was published in Current Biology this week.
To get anywhere, you need to know which direction you’re currently facing and which direction you need to travel in. Previous studies have shown that mammals like bats have neurons called “head-direction cells” that signal the direction they’re currently facing, and work with London cab drivers found that they first calculate the direction they need to head in when working out a route. “This type of 'homing signal' has been thought to exist for many years, but until now it has remained purely speculation,” says Hugo Spiers of University College London.
To see if there’s actually a part of the brain that tells us which direction to travel when we’re navigating, Spiers and colleagues recruited 16 volunteers to explore a simple square room simulated on a computer. Each of the walls have a different landscape photo and each corner contains a different object. Once they were familiar with the space, the volunteers were plopped down in one of the virtual corners, faced in a certain direction, and then asked to navigate to an object in another corner. Meanwhile, their neural activity was recorded using functional MRI.
“In this simple test, we were looking to see which areas of the brain were active when participants were considering different directions,” Spiers explains in a news release. “We were surprised to see that the strength and consistency of brain signals from the entorhinal region noticeably influenced people’s performance in such a basic task.”
The entorhinal region (pictured) is the part of the brain that tells you which direction you’re facing and which direction you should be facing as you move towards your destination. It’s where our sense of direction comes from, they found, and the quality of the signals from this brain region determines how good your navigational skills are.
“Your internal ‘compass’ readjusts as you move through the environment,” study author Martin Chadwick of UCL says. “For example, if you turn left then your entorhinal region should process this to shift your facing direction and goal direction accordingly. If you get lost after taking too many turns, this may be because your brain could not keep up and failed to adjust your facing and goal directions.”
Images: shutterstock.com (top), Hugo Spiers, UCL (middle)